Reply to "Valves"

Bowl or pocket-porting concentrates on the volume directly below the valve seat rather than the whole port. Since we know the bottom of the exhaust port from the turn outward is pretty much useless area (ala 4-V exhausts), there really no sense in opening this up on your 2V heads. The turn from vertical to horizontal is also worked to a larger radius, but this is dangerous with Cleveland heads- see the photos I published in the April POCA news of various cut-away heads and how thin this area really is. All porting should properly be done by an expert with a flow bench to incrementally check the effect, but nearly anyone can do a little pocket-porting without too much fear of screw-ups. Incidentally, Dan may be correct- 'bigger' often doesn't translate to' more power', even if the worked port flows more air. Theres a new (to me anyway) technique being used by porters that involved squirting Dykem metal-dye into the flow-bench airstream, then analyzing the resulting dye patterns in the ports and combustion chamber. Good write-up w/photos in the latest Circle Track magazine.